Hydrogen and electricity at once: An alkaline-acidic ethanol electroreformer

Abstract

This study presents the results of an alkaline-acidic ethanol electroreformer producing hydrogen and electricity simultaneously. This is due to the pH gradient between an alkaline anolyte/fuel (1 mol/L ethanol and 4 mol/L KOH) and an acidic catholyte/comburent (1 mol/L H2SO4), separated by a K+-pretreated Nafion® 211 membrane to prevent chemical neutralization, resulting in an extra electromotive force. At 70 °C, the electroreformer delivers a maximum power density of 23 mW cm−2. An increase in the flow rate from 0.17 to 1.12 mL min−1 is also beneficial due to the mass transport enhancement. Finally, over the stability tests for 3 h at 50 °C and a flow rate of 1.12 mL min−1, it is possible to produce H2 at an average rate of 0.218 and 0.267 STP m3 m-2h−1, and an average energy of 0.0877 and 0.0997 kWh m−2 in recirculation and single-pass mode, respectively. The worse performance in the recirculation mode seems to be due to the accumulation of the ethanol electro-oxidation products, resulting in the poisoning of the catalyst surface.